1. Field of the Invention
This invention relates generally to roof ventilating devices and specifically to a roof vent for ventilating the attic space of a building with a pitched roof.
2. Description of the Prior Art
The need to ventilate air within an attic is well recognized. Without ventilation, condensation may occur which can spot and damage ceilings, and it is more costly to air condition the building during the warmer months.
Although forced-convection ventilators are available, it is often preferable to allow natural circulation of air within the attic by vents located both near the peak of the roof and in the underside of the eaves. Such vents can be simple, be energy efficient and provide minimal aesthetic degradation to the roofline.
Vents on a pitched roof must prevent water running down a roof or wind-driven rain from entering the attic. One such vent of prior art for use on pitched roofs is disclosed in U.S. Pat No. 2,300,842 (Leslie). A difficulty with prior art vents of this type exists when installing the vent on an existing roof. Because the vent is a one-piece unit, it must be installed from underneath the roof or fastened through the shingles and caulked with sealant at its flashing. A vent which can be readily fastened from the rooftop but within the vent enclosure itself may allow easier retrofitting of existing roofs.
U.S. Pat. No. 5,394,663 and U.S. Pat. No. 6,293,862 disclose vents of two-piece construction. While these designs allow simplified installation, they are designed and arranged to receive a plumbing vent pipe or exhaust fan duct and not to maximize ventilation of an attic space.
To promote natural circulation, resistance to air flow should be minimized. The larger the area of a vent""s opening(s), the less resistance there is to air flow. For aesthetic reasons and to minimize potential wind damage, vents are preferably widened rather than made taller in order to increase air flow.
A fairly recent development in roof vents is that of the ridge vent, as typified by U.S. Pat. No. 5,174,076 or U.S. Pat. No. 5,797,222. The ridge vent boasts the advantage of being disposed at the highest locations in a roof top and have maximum width to promote ventilating and prevent stagnant pockets of air within an attic. Unfortunately, because of the difficulty inherent in installing a ridge vent in an existing roof, their use is essentially limited to new construction.
A vent which can be installed on the pitched portion of a roof, yet which is available in greater widths, is desirable. U.S. Pat. No. 6,202,372 shows just such a vent. However, as with the early prior art vents such as described by Leslie, this vent is of one-piece construction. For installation on an existing roof, it poses the difficulties mentioned above.
A primary object of the invention is to provide a roof vent for ventilating attic space of a building with a pitched roof which is easily installed on a new roof.
Another object of the invention is to provide a roof vent for ventilating attic space which is easily and quickly installed on an existing pitched roof from the rooftop.
Another object of the invention is to provide a roof vent for ventilating attic space which is installed on an existing pitched roof which does not require fastening at external flashing or the use of sealing compound.
Another object of the invention is to provide a roof vent for ventilating attic space which is available in varying widths to meet the unique demands of each installation and to promote ventilation.
Another object of the invention to provide a roof vent for ventilating attic space which is aesthetically pleasing.
The objects identified above, as well as other features and advantages of the invention are incorporated in an apparatus of two piece construction for ventilating the attic space of a pitched-roof building, comprising a base formed by a plate with angled tracks surrounding a opening therein to be first mounted over an opening in the roof, and a hood which covers the openings from water ingress and which is designed and arranged to slide into and be captured by said angled tracks without the use of additional fasteners. The hood includes a screened opening which faces the leeward side (i.e. facing the downward slope of the roof) to allow weathertight ventilation and to exclude small animals. Because the vent is installed in a two step process, the base is designed to be fastened from the rooftop in locations internal to the vent. The vent is designed for manufacture in varying widths to accommodate varying air flow and roofing requirements.